I would've thought that the average shopping mall is heating/cooling a lot more space (including high ceilings), a lot more often, and often during the day when solar is active and many households are empty? Large businesses run heating, cooling and lighting at times when I, being home, would not bother.

I knew someone who owned a small shopping centre and years ago he'd already put solar on the roof and was charging tenants for electricity he was soon-enough getting "for free" (given the installation paid for itself fairly quickly).

Here's an example of one in Australia - panels on the shopping centre's roof, and then solar canopies over the parking areas: https://binged.it/3vKGbm5 (Bing Maps since Google Maps has older satellite images for that area)